International conference on Frontiers in Chemical Technology 2020 (FCT 2020)
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/21614
Browse
2 results
Search Results
Item Detailed evaluation of methylated and acetylated products of cinnamon leaf oil against Aedes aegypti(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Medagedara, H. K.; Paranagama, P. A.; Gunaratna, Medha J.Aedes aegypti is a known vector of several viruses including Yellow fever, Dengue, Chikungunya and Zika virus. Two potential Aedes aegypti mosquito repellents; methyl eugenol and acetyl eugenol were semi-synthesized using eugenol extracted from cinnamon leaf, which is the main constituent in cinnamon leaf as well as in other plant leaf extracts like maduruthala and clove oil. Methyl eugenol was semi-synthesized using methyl iodide as a methylation precursor and acetyl eugenol was semi-synthesized using acetic anhydride, triethylamine base and catalytic amount of DMAP. Synthesis reactions were monitored using TLC and products were purified using flash silica columns. Formations of desired products were confirmed using GC-MS analysis. A diluted series (0.6-8 mg/ mL) was prepared for these semi-synthesized compounds and for the cinnamon leaf extract using ethanol and tested separately for their mosquito repellency using arm-in-cage tests followed by standard WHO methods. Experiments were performed on twenty volunteers in triplicates. Effective dose (ED99) for each repellent was calculated using beta regression analysis. Current study suggests that all compounds tested were effective mosquito repellents. Their ED99 varied as; cinnamon leaf extract (5.80) > methyl eugenol (5.41) > acetyl eugenol (5.13). Acetyl eugenol could be a potential safe repellent as its ED99 was achieved at a lower concentration and due to the absence of any side effects on skin when applied. Both maduruthala and clove oil contained significant contents of eugenol and clove oil had slight amounts of acetyl eugenol which could be extracted to synthesize repellent compounds or use directly in future.Item The OSMAC effect on the production of secondary metabolites by the endolichenic fungus, Curvularia trifolii(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Lekamwasam, C. J.; Paranagama, P. A.; Gunaratna, Medha J.Fungi are a very diverse group of organisms that can produce a vast number of pharmacologically active secondary metabolites. Fungi also have the ability to produce numerous secondary metabolites from a single strain. In this study, the One Strain Many Compounds (OSMAC) approach was used to observe the biosynthetic potential of endolichenic fungus, Curvularia trifolii isolated from Usnea sp. in Sri Lanka. Under the OSMAC approach, the variation of the metabolic profile of the fungus when cultured in different culture media was investigated. Culturing in Potato Dextrose Broth (PDB) medium resulted in the elution of two peaks in High- Performance Liquid Chromatographic (HPLC) study while four major peaks resulted from Yeast Potato Dextrose Broth (YPDB) medium cultures. Five major peaks eluted from Oatmeal extract broth (OEB) medium cultures and two major peaks from Rice-Yeast Broth (RYB) medium cultures. The bioactivities of crude extracts from each culture media were investigated using antioxidant, antibacterial, and anti-inflammatory assays and analyzed using Graph Pad Prism software. The crude extract of OEB showed a comparatively high antioxidant activity with ABTS radical scavenging assay with an IC50 value of 0.501 ± 0.036 mg mL-1 while the crude extract of YPDB showed a comparatively high anti-inflammatory activity with human red blood cell stabilization assay with an IC50 value of 0.151 ± 0.026 mg mL-1. The crude extract of RYB showed the highest antibacterial activity against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis bacterial strains upon analysis using agar-well diffusion method. The study confirms the variation of metabolic products and associated bioactivities of Curvularia trifolii with the variation of its culture medium.